Synchronized Ca2+ Dynamics in Glomeruli-Like Human Aldosterone-Producing Cell Clusters in Vitro

Objective: Primary aldosteronism (PA) is the leading cause of secondary hypertension. A curable subtype of PA, known as Aldosterone-Producing Adenoma (APA), is characterized by an excessive and autonomous aldosterone production. In the normal adrenal cortex, zona glomerulosa cells are organized into rosette-like structures, the glomeruli, which are critical for coordinated intracellular Ca2+signaling and regulated aldosterone production. The aim of this study was to determine whether multicellular rosette organization governs coordinated Ca2+ signaling in human zona glomerulosa cells from APA and normal adjacent adrenal cortex (AAC) cells upon angiotensin II (Ang II) stimulation in vitro. Design and method: We monitored the Ca2+ variations in aldosterone-producing APA and AAC cells upon Ang II stimulation using the Ca2+-sensitive Fura-2 dye and confocal fluorescence microscopy in living cells. The recorded Ca2+ signals were analyzed using clustering analysis based on cell-to-cell correlation. Results: After 24 hours in culture, both APA and AAC cells were organized into rosette-like clusters that resemble the glomeruli structures of the intact zona glomerulosa. Functional statistical and clustering analysis revealed synchronous intracellular Ca2+ activity among cells within the same cluster, with no synchrony observed between different clusters. No significant differences in intracellular Ca2+ synchronicity were detected between APA cells and AACs. Conclusions: Our study shows the in vitro formation of aldosterone-producing cell clusters from isolated single cells mimicking the in vivo structure of adrenal glomeruli. Additionally, our findings highlight the coordinated Ca2+ activity within these clusters, underscoring the functional significance of cluster organization and offering a potential new target mechanism for a therapeutic approach to PA.